Blinds originally serve the purpose of adjusting or blocking the rays of light which are introduced through a building opening into an interior. To meet a demand for a comfortable residential space, blinds are also required to have an element for providing a better interior atmosphere as well as the functions to adjust and block the light. Thus, various ideas have been put to practice in such a way as reducing the width of slates for giving a light visual impression or coloring the slats with soft quiet hues, but all such efforts have not brought satisfactory results.
With presently available blinds, much importance is attached to the functions to adjust and block the light, and slats are made of light-shielding materials such as a light alloy. Therefore, even if slats have soft colors, they look dark as long as viewed from the interior space in the daytime, thereby reducing the effect of the intended interior atmosphere.
Furthermore, conventional blinds are utterly lacking in any technical idea for positively utilizing daylight to provide an excellent atmosphere in the interior space. The applicant has proposed in Japanese patent application No. 62-239948 (Japanese laid-open patent publication No. 64-83795) a blind which positively utilizes daylight to provide an excellent atmosphere in the interior space, without impairing the original functions of the blind to adjust and block the light.
The proposed blind has parallel slats angularly movable simultaneously about their own longitudinal axes, each slat having a graphic pattern forming region on a base board of transparent material. The base board has, in its cross section perpendicular to the longitudinal axis thereof, a central surface, a first bent surface bent obliquely upward from one edge of the central surface, and a second bent surface bent obliquely downward from the other edge. When the slats are angularly moved and tilted at a predetermined angle, the graphic pattern forming regions of the respective slats are combined with each other to produce a significant graphic pattern for an observer on the entire blind.
The graphic pattern forming region is a region formed of a light-shielding paint or film, and the significant graphic pattern is a graphic pattern which is formed on the entire blind when the graphic pattern forming regions of individual slats are combined to give the observer in the interior space some impression through the visual sensation. Such graphic patterns include a pattern formed by the projected light from behind the blind onto the floor or wall (projection type), and a pattern formed on the entire blind by the reflected light from graphic pattern forming regions (direct-type) direct viewing type.
However, the above proposed blind has the following problems to be solved:
When the significant graphic pattern produced by the graphic pattern forming regions on the base boards of the slats has disappeared as the blind is closed, an insignificant pattern, or a pattern which may be uncomfortable to some people, may be formed by the graphic pattern forming regions, making the interior atmosphere uncomfortable rather than improving it.
Since the graphic pattern forming regions are fixed to the slat base boards, when the user is bored with the significant graphic pattern which is produced, the user has no choice other than replacing the blind as a whole. This poses a problem when the user wants to change the interior atmosphere depending on the type of the guests or the change of season.